U50488 inhibits HIV-1 expression in acutely infected monocyte-derived macrophages

Opioids may play an immunomodulatory role in the pathogenesis of human immu nodeficiency virus-1 (HIV-1) infection. Recently, synthetic kappa -opioid r eceptor (KOR) ligands have been found to have anti-human immunodeficiency v irus type 1 activity in acutely infected brain macrophages. In the present study, we investigated whether the selective KOR ligand U50488 would exert such an anti-HIV-l effect in acutely infected blood monocyte-derived macrop hages (MDM). Treatment of acutely infected MDM with U50488 induced a concen tration-dependent inhibition of HIV-1 expression. The dose-response relatio nship of U50488 was U-shaped with a peak effect observed at 10(-13) M, whic h was evident at both 7 and 14 days post-infection. The KOR antagonist nor- binaltorphimine blocked the anti-HIV-l effect of U50488 by 73%, indicating involvement of a KOR-mediated mechanism. Also, expression of KOR mRNA and b inding activity with a fluorescence-labeled KOR ligand supported the existe nce of KOR on MDM. Antibodies to the beta -chemokine, RANTES (regulated on activation normal T-cell expressed and secreted). but not to various other cytokines, blocked U50488 inhibition by 56% suggesting that the anti-HIV-l effect of U50488 involved, in part, the production of RANTES by MDM. Taken together, these in vitro findings support the anti-HIV-l property of U50488 , and suggest that KOR ligands may have therapeutic potential for treating patients with acquired immunodeficiency syndrome. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.